Drawing bench



C. HLZER DRAWING BENCH Filed Dec.

July 28, 1964 Nlwnfl, S. sfmrwd( Pffmwey- United States Patent O 3,142,376 DRAWING BENCH Carl Hlzer, Solingen, Germany, assigner to T. H. Kieserling & Albrecht, Solingen, Germany Filed Dec. l2, 1958, Ser. No. 780,078 Claims. (Cl. 20S- 3) The invention relates to a chain drive, and more particularly to a chain drive for a draw bench having a stationary drawing die and a drawing carriage reciprocably movable to and from the die and driven by a chain.

Chain drives for actuating movement of the carriage member of a draw bench commonly are of one of two types. In one of these types of draw bench drives, an endless chain is trained over a guide pulley and over a drive sprocket which actuates movement of the chain in one direction. The carriage member to which the wire to be drawn through the die is attached is provided with a hook which may be engaged with that strand of the chain which is moving away from the die so as to draw the wire. When the carriage member reaches the end of the drawing stroke and the hook approaches the drive sprocket or the guide pulley provided at the far end, the hook is disengaged from the chain and the carriage is returned to its position near the die for the next drawing stroke. The return of the carriage member is either actuated by gravity, the path of travel being inclined towards the die, or a separate endless return chain is provided to which the hook may be engaged for the return travel of the carriage member.

In the other type of chain drive which is commonly used, the carriage member is permanently connected to an endless chain which is driven to move alternately in opposite directions so as to drive the carriage to and from the die. This invention is concerned with improvements in the latter general type of chain drive.

The drive chain or chains and the associated drive pulleys constitute an appreciable portion of the weight of the draw bench, and their rst cost is a significant factor in the overall cost of the equipment.

An object of the invention is, therefore, a reduction of the weight of the drive chain and of the associated pulleys in a chain drive of the described type.

Another object is the provision of such a chain drive which is less costly to manufacture or to replace than the drives of the prior art.

With these and other objects in View, the present invention contemplates replacing the conventional endless chain by a chain having two ends, one end being fastened to the carriage member, the chain being trained over a drive sprocket which is part of a drive means for alternately moving the chain in opposite directions. Guides extend from the drive sprocket to the carriage and guide the chain in such a manner as to prevent it from kinking. As the chain is driven alternately in opposite directions, the carri-age is not only pulled by the chain away from the die so as to draw the wire through the die, but the carriage is also pushed back towards the die by the chain.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction `and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

FIG. 1 shows a side elevation of a preferred embodiment of the invention, and

FIG. 2 is a fragmentary sectional View of a device similar to that of FIG. 1, taken along line II-II of FIG. l.

Referring now to the drawing, there is generally shown ICC a die support 1. Two upper guideways 2 and two lower guideways 2a for guiding and constraining chains 3 eX- tend from die support 1 toward a drive box 4 containing the necessary gearing and controls for alternately moving two drive sprockets 5 in clockwise and counterclockwise direction the drive sprockets being mounted on a common shaft on opposite sides of drive box 4. A carriage member 6 is arranged between the guideways forv travel to and from the die held in support 1 for drawing a wire through the die la in a well-known manner, the carriage member being equipped with means 6a for releasably gripping the wire. Such means which are not part of the present invention are not shown in detail.

The ends 3a of two roller chains 3 are laterally fastened to the carriage member 6. Each chain 3 is trained over a drive sprocket 5 in a tangential plane which passes through the die opening 1b of the die 1a in die support 1. During the drawing stroke, the ends 3a of chains 3 are under axial tension and do not exert any forces laterally on the guideways 2 in which they are guided in linear paths by guide rolls 7.

The free, slack ends 3b of chains 3 are guided from drive sprockets 5 in guide ways 2a which are curved towards guideways 2 and form a unitary structure therewith in which the two guideways on either side of the path of carriage member 6 extend in substantially parallel alignment. The upper guideways 2 are each equipped with a lateral slot which accommodates the fastening member connecting the carriage member 6 to the ends 3a of chains 3. The lower guideways 2a completely envelop the slack ends 3b of chains 3 so as to protect them against dust and other atmospheric inuences. The closed channels formed around the chain ends 3b by guideways 2a may be llooded by a lubricant a portion of which is also transmitted to the ends 3a of chains 3 by the reciprocating movement of the chains which lubricant picked up in guideway 2a on drive sprockets 5 and guideways 2 from which it is transferred in sufficient amounts to chain ends 3a to assure adequate lubrication of the latter.

In the chain drive illustrated in FIG. 1, each pin of the roller chain 3 carries one guide roll 7, the guide rolls being arranged on successive pins on alternate sides of the chain.

In the embodiment of the invention shown in FIG. 2, each pin of the roller chains 3 carries two guide rolls 7 at either end thereof. Such an arrangement is preferred although it is applicable only when the individual chain links are of suflicient length to accommodate the rolls which are preferably of a diameter greater than the thickness of the chain as best seen in FIG. 2.

The afore-described device operates in the following manner:

The position of the carriage member 6 at the start of the drawing stroke is illustrated in FIG. 1. Upon movement of the drive sprockets 5 in a clockwise direction, the chain ends 3a are set under tension due tothe drag of the drawn wire and the carriage member 6 is moved to the right drawing the wire through the die la. The slack ends 3b of chains 3 are gradually pushed into the guideways 2a. Engagement of the rolls 7 with the upper and lower walls forming the guideways 2a prevents buckling of the chain ends 3b. When the carriage member 6 reaches its terminal position remote from die l, the gripping means 6a associated with the carriage member 6 are made to release the wire and the direction of movement of drive sprockets 5 is reversed so as to pull free chain ends 3b out of lower guideways 2a. The upper chain ends 3a are urged into their guideways 2 and push the carriage member 6 back towards the die l. But for the engagement of rolls 7 with the upper and lower walls of guideways 2, the chain ends 3a would buckle under the frictional resistance ansa-are 3 offered by carriage member 6 as it is moved back toward the die support 1 although the workpiece is released by gripping means 6a and exerts no force on the chain portion moving toward support 1.

It has 4been found that very substantial compressional forces can be transmitted in the afore-described manner by a precisely guided chain, so that the device of the invention is not only applicable to draw benches but may even find use in metalworking machines in which metal is deformed by being pushed through a calibrated opening.

As` compared to the conventional draw bench equipped with an endless chain trained over a guide pulley and a drive sprocket, the device of the present invention is capable of operating with a chain of substantially one half the length of that used with the conventional arrangement. There is furthermore no need for a guide pulley for reversing the direction of travel of the chain. The savings in weight and in first cost resulting from this difference may be substantial in view of the very demanding requirements for drive chains in draw benches.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of a draw bench differing from the types described above,

Without further analysis, the foregoing will so fully reveal the gistof the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. A drawing apparatus comprising, in combination, an elongated support having two parallel adjacent elongated rigid guideway means; a die member having a die opening and located at one end of said elongated support; a housing at the other end of said support; a carriage means mounted on said support for reciprocating movement between a Vfirst terminal position closer to said die member and a second terminal position closer to said housing and adapted for drawing a wire through said die opening only during movement from said first to said second terminal position; flexible chain means having two ends, one of said'ends being fastened to said carriage means and guided along the length thereof in one of said guideway means and the other end being free and guided along the length thereof in the other of said guideway means, said chain means passing through said housing; reversible drive means in said housing engaging said chain means and being operable to move said chain means in opposite directions for reciprocating said carriage means between said terminal positions, said chain means having such a length that said other e"nd is spaced a short distance from said drive means when said carriage is in said rst terminal position whereby the drawing force tensions the portion of said chain means between said one end thereof and said drive means during movement of said carriage means from said first to said second terminal position while the workpiece exerts no force on said portion of said chain means during movement of said carriage means from said second to said rst terminal position and buckling of said portion of said chain means during return movement of said carriage means from the second to the first terminal position is prevented by said guideway means.

2. A drawing apparatus as set forth in claim 1 wherein said guideway means are closed at said other end of said support and form a closed chamber with the interior of said housing; and a lubricant in said chamber adapted to be displaced during movement of said other end of said chain means in said other guideway means.

3. A drawing apparatus as set forth in claim 1 wherein said chain means is composed of a plurality of links and pivot means connecting said links, and a plurality of rollers mounted on said chain means for turning movement about axes extending in the direction of the axes of said pivot means; and wherein said guideway means have parallel guide faces between which said rollers are located.

4. An apparatus as 'set forth in claim 1 wherein said chain means include a pair of flexible chains, one pair of ends of said chains being fastened to opposite sides of said carriage means and the other pair of ends of said chains being loose; and 'wherein said support includes two parallel supporting members, each guideway means including two guideways respectively located in said supporting members.

5. A drawing apparatus comprising, in combination, elongated supporting means having rigid guideway means; a die support having a die opening and mounted at one end of said elongated supporting means; carriage means mounted on said supporting means for reciprocating movement in the direction of said guideway means between a iirst position located nearer to said die support and a second position located farther from said die support, said carriage means having releasable gripping means for engaging a workpiece in said first position and for drawing the workpiece through said die opening during movement from said first position to said second position, said gripping means being adapted to be opened in said second position for releasing the workpiece; reversible drive means located at the other end of said elongated supporting means in the region of said rigid guideway means; and exible chain means having two ends and being drivingly engaged by said drive means intermediate said ends thereof, one of said ends of said chain means being free and the other end of the same being secured to said carriage means, at least the portion of said chain means between said other end of said chain means and said drive means being confined and guided in said guideway means so that the drawing force required for pulling the workpiece through said die opening tensions said chain means when said chain means is operated by said drive means to pull said carriage means with said gripping means and workpiece from said rst to said second position, while the workpiece exerts no force on said portion of said chain means and only said carriage means with said gripping means is pushed by said portion of said chain means after the workpiece is released by said gripping means in said second position and said chain means is operated by said drive means to push said carriage means from said second position to said first position so that buckling of said portion of said chain means is prevented by said rigid guideway means.

References Cited in the file of this patent UNITED STATES PATENTS 898,550 Broderick Sept. 15, 1908 1,711,825 Barnhart May 7, 1929 2,304,026 Schonwald Dec. 1, 1942 2,583,708 Rose Ian. 29, 1952 2,696,122 Clark Dec. 7, 1954 2,841,998 Troche July 8, 1958 2,898,101 Hannum et al Aug. 4, 1959 

1. A DRAWING APPARATUS COMPRISING, IN COMBINATION, AN ELONGATED SUPPORT HAVING TWO PARALLEL ADJACENT ELONGATED RIGID GUIDEWAY MEANS; A DIE MEMBER HAVING A DIE OPENING AND LOCATED AT ONE END OF SAID ELONGATED SUPPORT; A HOUSING AT THE OTHER END OF SAID SUPPORT; A CARRIAGE MEANS MOUNTED ON SAID SUPPORT FOR RECIPROCATING MOVEMENT BETWEEN A FIRST TERMINAL POSITION CLOSER TO SAID DIE MEMBER AND A SECOND TERMINAL POSITION CLOSER TO SAID HOUSING AND ADAPTED FOR DRAWING A WIRE THROUGH SAID DIE OPENING ONLY DURING MOVEMENT FROM SAID FIRST TO SAID SECOND TERMINAL POSITION; FLEXIBLE CHAIN MEANS HAVING TWO ENDS, ONE OF SAID ENDS BEING FASTENED TO SAID CARRIAGE MEANS AND GUIDED ALONG THE LENGTH THEREOF IN ONE OF SAID GUIDEWAY MEANS AND THE OTHER END BEING FREE AND GUIDED ALONG THE LENGTH THEREOF IN THE OTHER OF SAID GUIDEWAY MEANS, SAID CHAIN MEANS PASSING THROUGH SAID HOUSING; REVERSIBLE DRIVE MEANS IN SAID HOUSING ENGAGING SAID CHAIN MEANS AND BEING OPERABLE TO MOVE SAID CHAIN MEANS IN OPPOSITE DIRECTIONS FOR RECIPROCATING SAID CARRIAGE MEANS BETWEEN SAID TERMINAL POSITIONS, SAID CHAIN MEANS HAVING SUCH A LENGTH THAT SAID OTHER END IS SPACED A SHORT DISTANCE FROM SAID DRIVE MEANS WHEN SAID CARRIAGE IS IN SAID FIRST TERMINAL POSITION WHEREBY THE DRAWING FORCE TENSIONS THE PORTION OF SAID CHAIN MEANS BETWEEN SAID ONE END THEREOF AND SAID DRIVE MEANS DURING MOVEMENT OF SAID CARRIAGE MEANS FROM SAID FIRST TO SAID SECOND TERMINAL POSITION WHILE THE WORKPIECE EXERTS NO FORCE ON SAID PORTION OF SAID CHAIN MEANS DURING MOVEMENT OF SAID CARRIAGE MEANS FROM SAID SECOND TO SAID FIRST TERMINAL POSITION AND BUCKLING OF SAID PORTION OF SAID CHAIN MEANS DURING RETURN MOVEMENT OF SAID CARRIAGE MEANS FROM THE SECOND TO THE FIRST TERMINAL POSITION IS PREVENTED BY SAID GUIDEWAY MEANS. 